The subject invention relates to a device for generating mechanical vibrations. More particularly, it relates to an electromagnetic vibration device utilizing non-linear sectionalized waveform plate springs.
Utilization of the principle of electromagnetic shock excitation for designing drivers has been used in the past in many forms of vibrating devices. Thus far, however, the application of vibrating machines is still limited and their energy saving effects and various other potential advantages have not been fully demonstrated nor made practical in wide application.
Prior efforts in this field have largely laid emphasis on structural forms and mass combinations, and two crucial problem areas have not been seriously considered and addressed, namely: (1) the design, manufacture, and parameter selection for the vibration component, and (2) the control of mechanical vibration.
Mechanical vibration is a complex physical phenomenon. Its amplitude, frequency, energy dissipation, and limits of stored and released energy depend on numerous factors including: (a) rigidity characteristics of the vibration component, (b) structural damping of the vibration component, (c) magnitude, frequency, and other characteristics of a shock exciting force, (d) magnitude and type of external damping, and (e) expected variations and changes in load.
If the vibration component is a linear spring (with constant rigidity), damping is directly proportional to velocity and a linear vibration system is formed. When such a system is applied to vibration machines, and disadvantages are that the limit of stored energy is relatively small and the stability of vibration is rather poor. For this reason, efforts have been made in the field toward non-linear vibration devices many of which are available today.
Non-linear vibration systems of the prior art, however, have also been less than satisfactory. Certain non-linear springs may stabilize a systems inherent frequency, and achieve larger vibration amplitudes at lower cost of power consumption, but are applicable only in ordinary operating conditions which do not require higher precision and accuracy in directional vibration, or consistent resonance and vibrator stability during fluctuating load conditions in mass, flexibility, and damping. Furthermore, conventional non-linear vibration systems are not suitable for effective operation when a vibration frequency different from the exciting frequency is required, or when it is used to drive a large vibration system. Also, changes in the mass of the external load, in rigidity, in damping, or combined random changes of varying kinds, will result in instability of vibration. For these reasons, the range of applications of previously known non-linear vibration devices have been limited. Alternatively, complicated and costly electrical feedback devices must be employed. Consequently, a complex supplemental system is usually required for providing electrical control or other kinds of assistance to non-linear vibrators of the prior art in order to accommodate operating conditions of the type mentioned above. These complex supplemental systems invariably add to the cost of energy consumption as well as restricting the practical adaptability of the vibrator to different applications by causing the overall structure to be bulky and inflexible.
Although research and development of non-linear vibration systems has had a history of many years; due to the vastness, richness, and variability of this field, a series of fundamental problems remained unsolved prior to the instant invention, including those mentioned above. For example, how many limiting rings of the phase space are there in an ordinary differential system of n.sup.th order (i.e. how many basically different stable vibration types are there in a non-linear vibration system which may be described by an ordinary differential equation of n.sup.th order)? Of the twenty three problems proposed by Hilbert nearly a century ago, this is the sixteenth one and the one for which the least progress has been made. Although in theory this problem has not been solved thoroughly, the instant invention, in the field of non-linear electromagnetic vibration, provides a practical solution in utilizing selective elastic vibration components of selective parameters and rigidity in combination for effecting a controlled stable vibration, in the absence of complex external electrical supplemental feedback controller devices.
The difficulties suggested in the preceding are not intended to be exhaustive, but rather are among many which may tend to reduce the effectiveness and satisfaction with prior vibration devices. Other noteworthy problems may also exist; however, these presented above should be sufficient to demonstrate that non-linear electromagnetic vibration devices appearing in the past will admit to worthwhile improvement.